I have a mazda miata (1990) with an LS6/4L60E.

It's been pretty hot lately and after even mild spirited driving, I am getting boilover after I shut the engine off (3-4 minutes after engine is shut off).

I am wondering if maybe I have the fan relay wired incorrectly.

On a vette or a camaro, does the fan run after the engine is shut off?

I am using a Trans Am PCM. The fan power is tapped off the ignition power. Should it be tapped off of the battery?

Also, my intake air temperature is about 145 F at idle at 75F ambient in the evening. That seems awfully high. How does this compare with a Trans Am/Corvette/Camaro?

Thanks,

Sam

 

Fans are PCM managed so when motor is off so are the fans. You could put a thermo-controler on your setup to run after motor is off.
Are you runing enough coolant mix?

 

On my '98, my tuner has it set up to where the fans run even after the engine is shut off. Of course, that's if the engine temp is high enough.

 

That is probably what I will have to do.

I am running about 30/70 mix for the summer.

Is it possible my themostat has gone bad?

What should the temperature hold at on most of these cars?


Sam.

 

Definately have your radiator cap checked.
Boilover usually means loss of pressure in the system.

 

That was the first thing I replaced. I just replaced my thermostat. Hopefully that will resolve the problem.

Sam

 

It may just be that the engine bay is so confined that the heat has nowhere to go. It might be necessary to find a way to vent the excess heat.

 

maybe it's losing pressure somewhere else ...even a headgasket.

 

I replaced the thermostat earlier today and haven't had any problems since. It was about 100 degrees and I was in traffic. Seems to be O.K. now.

I think I will add some louvers to the hood to bring the underhood temps down. Its just too hot under there.

Thanks for all the advice.

Sam

 

Good, that thing must fly.
What is the Miata's weight?

 

It gained a bit more weight than you would expect, because I didn't want the weak rear end that miata had. I went with a 2003 Lincoln LS rear end assembly.

Weight numbers:

Front 1400 Pounds
Rear 1240 Pounds (Full tank of gas)

Total 2640

Weight distribution 53/47

As far as how well it moves, it moves reasonably well for a rear wheel drive car. I put a TCI streetfighter torque converter in (probably a mistake). I am not able to apply only about 50% throttle before lighting up the rear end.

Even so, with street tires (using a Gtech Accelerometer / Pro) It records about 0-60 in 4.7 seconds. (I am not a very good driver and simply haven't gotten very good at applying the right amount of throttle - too much and its all over with a pretty lousy time - too little and I am not pushing is as much as I can).

I have no idea what it will do in the quarter mile.

I am planning on going to the track next wednesday to find out.

Sam

 

Put some drag radials on that thing, it needs more tire if you're spinning that easily.

I bet it moves out pretty good, heh.

Rob (Bad30th)